The process of conceptual development by which children acquire an understanding of the concepts of health as related to Acquired Immunodeficiency Syndrome (AIDS) is poorly understood; even less is known about the child's capacity to benefit from educational efforts to promote the acquisition of these "AIDS-related concepts." This research project has 3 major aims: 1) To identify the concepts in healthy children aged 5- 12 years, 2) To assess the socio-cultural and demographic variables associated with the child's understanding of these concepts, and 3) To evaluate the effectiveness of a school-based educational program on the promotion of AIDS-related conceptual development. To accomplish these aims, the study design incorporates both cross-sectional and longitudinal methods in a three-phase project spanning five years. In the first phase, normative data will be collected on a cross-sectional sample (N=210) of elementary school-aged children utilizing a structured interview designed by the principal investigator, the Structural Interview of AIDS-related Concepts (SIAC). Development of the SIAC was based on pre- existing, standardized research instruments of other health-related developmental concepts; results from a pilot study of the SIAC demonstrated that it is a well tolerated interview and is effective in the evaluation of the relevant developmental concepts. The second phase is a randomized trial of the efficacy of a school-based educational program in the promotion of the concepts of health related to AIDS. Classes at each grade level will be randomized to control and experimental groups. The SIAC will be administered to all study subjects (N= 210) on three occasions (pre- intervention, post-intervention, and 2-3 months later). The experimental group will receive three interventions: 1) a series of six 30-45 minute presentations about concepts of physical illness (utilizing AIDS as an example of one significant and major illness) will be presented by the principal investigator over a three week period to the classes in the experimental group, 2) teacher in-service, and 3) parent in-service. The difference in SIAC score between the pre-test and post-test(s) will be used as the outcome variable to compare the non-intervention control group and the experimental group. The third phase is a larger scale randomized trial, involving three to four schools (n=400-500 students), in which the classroom teachers will conduct the educational presentations. This project will provide information about what children know about the concepts of health related to AIDS and what they are capable of learning through school-based education. As such, it will provide guidance in the creation of developmentally-appropriate AIDS educational programs/